External Bone Fixation Strut with Nested Actuator
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Solution Overview
Problem
Current external bone fixation devices for stabilizing and healing bone fractures or deformities lack efficient mechanisms for precise adjustment and stabilization, particularly in adjusting the orientation and spacing of bone segments over time, which can impede the healing process.
Innovation Solution
The device incorporates a strut system with a threaded rod and sleeve configuration, an actuator, and a locking mechanism that allows for precise translation and rotation of the strut along its axis, enabling adjustable length and orientation of external bone fixation members to facilitate distraction or compression, thereby aiding in bone healing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a threaded rod and sleeve configuration is used for adjusting strut length, then the adjustment precision is improved, but the device complexity increases due to additional components
Solution Approach 1:
The threaded rod is nested within the sleeve, with the actuator positioned within the strut body. This nesting arrangement allows multiple adjustment components to be compactly integrated without significantly increasing the overall device footprint, thereby improving adjustment precision while minimizing the increase in device complexity.
2Reliability
If a locking mechanism is added to prevent actuator rotation, then the stabilization reliability is improved, but the ease of operation deteriorates due to additional locking steps
Solution Approach 1:
The locking mechanism is designed to automatically engage with the actuator when the strut reaches the desired length, eliminating the need for manual locking operations. The mechanism self-activates based on the positional relationship between the actuator and locking components, thereby improving stabilization reliability without compromising ease of operation.
3Adaptability or versatility
If the pivot axis is angularly offset from the strut axis, then the adaptability for different bone orientations is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The pivot axis is deliberately positioned at an angular offset from the strut axis, creating an asymmetric geometric relationship that enables the locking mechanism to effectively engage with the actuator. This asymmetric configuration provides adaptability for different bone orientations while the offset distance is optimized to balance manufacturing precision requirements with functional performance.
4Adaptability or versatility
If the threaded rod is translatable within the sleeve, then the adjustability of bone segment spacing is improved, but the stability during adjustment deteriorates due to potential slippage
Solution Approach 1:
The frictional interaction between the threaded rod and sleeve creates a passive feedback mechanism that provides continuous resistance to translation during adjustment. This friction-based feedback ensures stable, controlled movement of the threaded rod within the sleeve, preventing slippage while maintaining adjustability of bone segment spacing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a more precise and effective means of stabilizing bone segments, allowing for controlled adjustments that enhance the healing process by enabling gradual changes in bone alignment and spacing, promoting optimal bone growth and strength.
Implementation Method 1
The threaded rod includes a rod body that is elongate along the strut axis. The rod body defines an outer surface that is at least partially threaded, and the sleeve includes a sleeve body and a bore that extends at least into the sleeve body. The bore is configured to receive at least a portion of the threaded rod such that the threaded rod is translatable relative to the sleeve along the strut axis.
Implementation Method 2
The strut further includes an actuator supported by the strut body and threadedly attached to the threaded rod, such that rotation of the actuator relative to the rod about the strut axis translates at least one or both of the rod and the sleeve relative to the other of the rod and the sleeve along the strut axis.
Implementation Method 3
The strut further includes a locking mechanism supported by the strut body so as to be pivotal relative to the strut body about a pivot axis between a locked configuration whereby the locking mechanism prevents the actuator from rotating relative to the threaded rod, and an unlocked configuration whereby the locking mechanism does not prevent the actuator from rotating relative to the threaded rod.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The present application discloses embodiments related to an external bone fixation device configured to correct bone deformities or repair bone injuries. The device can include a plurality of bases configured to be attached to portions of a bone and a plurality of struts configured to be adjustable in length to change the position and orientation of the plurality of bases and the attached bone portions.